Nutritional support is indicated in patients who are malnourished or at risk of malnourishment. Common indications for enteral nutrition include dysphagia, mechanical ventilation preventing oral nutrition intake, the need to feed the gut distal to an obstruction or high-output fistula, and hypermetabolic disease states, such as burns and trauma. Parenteral nutrition is required when enteral nutrition is contraindicated, or when the GI tract has diminished function due to underlying conditions, including small bowel obstructions, paralytic ileus, short bowel syndrome, and fistulae. In most other conditions, it has been difficult to prove the efficacy of nutritional support over treatment without such support.
The ASPEN has published recommendations for the rational use of nutritional support. These emphasize the need to individualize the decision to begin nutritional support, weighing the risks, benefits, and costs. The guidelines also highlight the need to perform comprehensive nutrition assessments to identify patients who may benefit from aggressive nutrition interventions.
NUTRITIONAL SUPPORT METHODS
Selection of the most appropriate nutritional support method involves consideration of GI function, the anticipated duration of nutritional support, and the ability of each method to meet the patient’s nutritional requirements. The method chosen should meet the patient’s nutritional needs with the lowest risk and cost. For most patients, enteral feeding is safer and less expensive and offers significant physiologic advantages. An algorithm for selection of the most appropriate nutritional support method is presented in Figure 29–1.
Nutritional support method decision tree.
Prior to initiating specialized enteral nutritional support, efforts should be made to supplement food intake. Attention to patient food preferences, liberalizing diet orders, timing of meals in relation to diagnostic procedures and required medications, and the use of foods brought to the hospital by family and friends can often increase oral intake. Patients unable to eat enough at regular mealtimes to meet nutritional requirements can be given oral supplements as snacks or to replace low-calorie beverages. Oral supplements with different nutritional compositions are available to meet the specific needs of various clinical conditions. Formulations vary in fiber and lactose content, caloric density, protein level, and electrolyte concentrations.
Patients with functioning GI tracts who are unable to take adequate oral nutrition or safely swallow are appropriate for enteral nutritional support (tube feeding). Short-term enteral access devices can be placed into the nose or mouth and terminate in the stomach or small bowel. Examples are orogastric, nasogastric, nasoduodenal, and nasojejunal tubes. Bedside placement of short-term enteral access devices is typically successful; however, it may be difficult to achieve post-pyloric placement. Some patients will require fluoroscopic or endoscopic guidance to insert the feeding tube distal to the gastric pylorus. Correct feeding tube placement should always be confirmed radiographically prior to initiation of feeding. Long-term enteral access devices are placed directly into the stomach or small bowel, called tube enterostomies. Percutaneous ...